[en] The provenance postulate states that artifact raw material sources can be determined by chemical characterization as long as between-source chemical differences exceed within-source variation. For ceramics, successful differentiation of sources usually requires the measurement of a large suite of elements. While laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) can provide concentration data for nearly every element whose concentration is at or above 100 ng/g, it requires the use of 'matrix matched' standards for quantitative analysis. In this work, we report on the use of micro-PIXE to develop standards for the microanalysis of ceramics by LA-ICP-MS
Journal
Nuclear Instruments and Methods in Physics Research. Section B, Beam Interactions with Materials and Atoms; ISSN 0168-583X; 
; CODEN NIMBEU; v. 189(1-4); p. 378-381
; CODEN NIMBEU; v. 189(1-4); p. 378-381
[en] We theoretically investigate schemes to discriminate between two nonorthogonal quantum states given multiple copies. We consider a number of state discrimination schemes as applied to nonorthogonal, mixed states of a qubit. In particular, we examine the difference that local and global optimization of local measurements makes to the probability of obtaining an erroneous result, in the regime of finite numbers of copies N, and in the asymptotic limit as N→∞. Five schemes are considered: optimal collective measurements over all copies, locally optimal local measurements in a fixed single-qubit measurement basis, globally optimal fixed local measurements, locally optimal adaptive local measurements, and globally optimal adaptive local measurements. Here an adaptive measurement is one in which the measurement basis can depend on prior measurement results. For each of these measurement schemes we determine the probability of error (for finite N) and the scaling of this error in the asymptotic limit. In the asymptotic limit, it is known analytically (and we verify numerically) that adaptive schemes have no advantage over the optimal fixed local scheme. Here we show moreover that, in this limit, the most naive scheme (locally optimal fixed local measurements) is as good as any noncollective scheme except for states with less than 2% mixture. For finite N, however, the most sophisticated local scheme (globally optimal adaptive local measurements) is better than any other noncollective scheme for any degree of mixture.
Journal
[en] Purpose: To evaluate the results of interstitial radiotherapy of anorectal tumors. Patients and Methods: From 1972 to 1993, one of the authors treated 45 patients by an interstitial implant for anorectal tumors. Of these, 33 patients suffered from primary tumors, 19 from squamous carcinoma, 2 from basaloid carcinoma of the anus and the other 12 from primary adenocarcinoma of the rectum. Of 12 patients treated for local recurrence, 10 had adenocarcinoma and 2 squamous cell carcinoma. Of the 33 patients with primary tumors, 27 received a course of external-beam radiotherapy before the implant. The median follow-up was 35 months. Results: Local response depended on the tumor volume treated. All 21 anal tumors showed complete response, 5 patients developed local recurrence and 4 distant metastases; 3 died from their disease. Of 12 rectal adenocarcinomas, 9 responded completely, 4 patients developed local recurrence and 4 distant metastases; 6 died from their disease. In the last group of 12 patients who were treated for recurrent tumors, 7 responded completely. One patient developed local recurrence and 9 distant metastases, only 4 are alive. Conclusions: A combination of external-beam and interstitial radiotherapy is a relatively simple, non-mutilating, but well-tolerated and very effective method of treatment for early carcinoma of the lower rectum and a nus. (orig.)
[de]
Ziel: Die Auswertung der Ergebnisse der interstitiellen Radiotherapie anorektaler Geschwuelste. Patienten und Methode: Das Krankengut bestand aus 45 Patienten mit anorektalen Tumoren, die im Zeitraum von 1972 bis 1993 durch interstielle Implantate behandelt wurden. Von 33 Patienten mit primaeren Tumoren wurden 19 wegen spinozellulaerer, zwei wegen basozellulaerer Karzinome des Anus, weitere zwoelf wegen Adenokarzinomen des Rektums behandelt. Ausserdem wurden zwoelf Patienten wegen Lokalrezidiven, davon zehn wegen Adeno- und zwei wegen Spinozellularkarzinomen bestrahlt. Von den 33 Patienten mit primaeren Tumoren wurden 27 vor dem Implantat mit Teletherapie perkutan bestrahlt. Die mediane Nachbeobachtungszeit betrug 35 Monate. Ergebnisse: Der Behandlungserfolg war von der Tumorgroesse abhaengig. In der Gruppe von 21 Patienten mit Analtumoren, bei der eine komplette Tumorremission erreicht wurde, traten in fuenf Faellen Lokalrezidive, in vier Faellen Fernmetastasen auf, drei Patienten sind bisher verstorben. Bei zwoelf rektalen Adenokarzinomen wurde neunmal eine komplette Tumorremission erreicht, bei vier Patienten mit Fernmetastasen. Sechs Patienten verstarben. In der Gruppe von zwoelf Patienten, die wegen Lokalrezidiven behandelt wurden, kam es bei sieben zu einer kompletten Remission, bei einem davon entwickelte sich spaeter ein zweites Lokalrezidiv. Es traten neun Fernmetastasen auf, acht Patienten verstarben. Schlussfolgerung: Die Kombination der perkutanen Bestrahlung mit interstinellem Implantat erweist sich als relativ einfache, aber sehr effektive Methode der Behandlung von fruehen analen und tiefer liegenden Rektumkarzinomen. (orig.)Journal
[en] LaCl3:Ce and LaBr3:Ce scintillators are characterized by a high light yield and very fast nanosecond primary emission. To study scintillation mechanisms in these materials, we have measured low-temperature thermoluminescence. Both crystals exhibited prominent glow peaks below 100 K: LaCl3:10%Ce sample showed multiple glow peaks with two major ones at 65 and 66 K, whereas the LaBr3:0.5%Ce sample showed two major peaks at 65 and 75 K. Assuming first-order kinetics, the traps responsible for those peaks can be described by the following parameters: E=0.168 eV, s=1x1012 s-1; E=0.135 eV, s=1x109 s-1 for LaCl3:Ce and E=0.144 eV, s=1x1010 s-1; E=0.166 eV, s=1x1010 s-1 for LaBr3:Ce. The lifetimes of listed traps at RT are in the range of radiative lifetime of Ce3+ emission (0.5-50 ns)
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 537(1-2); p. 93-96
; CODEN NIMAER; v. 537(1-2); p. 93-96
[en] Optical quantum communication utilizing satellite platforms has the potential to extend the reach of quantum key distribution (QKD) from terrestrial limits of ∼200 km to global scales. We have developed a thorough numerical simulation using realistic simulated orbits and incorporating the effects of pointing error, diffraction, atmosphere and telescope design, to obtain estimates of the loss and background noise which a satellite-based system would experience. Combining with quantum optics simulations of sources and detection, we determine the length of secure key for QKD, as well as entanglement visibility and achievable distances for fundamental experiments. We analyse the performance of a low Earth orbit satellite for downlink and uplink scenarios of the quantum optical signals. We argue that the advantages of locating the quantum source on the ground justify a greater scientific interest in an uplink as compared to a downlink. An uplink with a ground transmitter of at least 25 cm diameter and a 30 cm receiver telescope on the satellite could be used to successfully perform QKD multiple times per week with either an entangled photon source or with a weak coherent pulse source, as well as perform long-distance Bell tests and quantum teleportation. Our model helps to resolve important design considerations such as operating wavelength, type and specifications of sources and detectors, telescope designs, specific orbits and ground station locations, in view of anticipated overall system performance. (paper)
Journal
New Journal of Physics; ISSN 1367-2630; ; v. 15(2); [35 p.]
; v. 15(2); [35 p.]
[en] We derive, and experimentally demonstrate, an interferometric scheme for unambiguous phase estimation with precision scaling at the Heisenberg limit that does not require adaptive measurements. That is, with no prior knowledge of the phase, we can obtain an estimate of the phase with a standard deviation that is only a small constant factor larger than the minimum physically allowed value. Our scheme resolves the phase ambiguity that exists when multiple passes through a phase shift, or NOON states, are used to obtain improved phase resolution. Like a recently introduced adaptive technique (Higgins et al 2007 Nature 450 393), our experiment uses multiple applications of the phase shift on single photons. By not requiring adaptive measurements, but rather using a predetermined measurement sequence, the present scheme is both conceptually simpler and significantly easier to implement. Additionally, we demonstrate a simplified adaptive scheme that also surpasses the standard quantum limit for single passes.
Journal
New Journal of Physics; ISSN 1367-2630; ; v. 11(7); [14 p.]
; v. 11(7); [14 p.]
[en] Lutetium iodide (LuI3) is a new addition to the family of Ce-doped lanthanide trihalide scintillating materials. Crystals of this material show hexagonal structure with density of 5.6 g/cm3 and have been grown by the Bridgman method. Under X-ray excitation this material exhibits broad, cerium based emission that peaks at 475 and 520 nm. The fastest and major component of scintillation time profile of LuI3:Ce emission decays with a 31 ns time constant. The light yield of LuI3:Ce for thin samples (∼0.2 mm) was estimated to be ∼50,000 photons/MeV
Journal
Nuclear Instruments and Methods in Physics Research. Section A, Accelerators, Spectrometers, Detectors and Associated Equipment; ISSN 0168-9002; ; CODEN NIMAER; v. 537(1-2); p. 279-281
; CODEN NIMAER; v. 537(1-2); p. 279-281